Different kinetics of lung clearance of technetium-99m labelled diethylene triamine penta-acetic acid in patients with sarcoidosis and smokers

✍ Scribed by Ingela Brådvik; Per Wollmer; Eva Evander; Hildur Lárusdóttir; Berith Blom-Bülow; Björn Jonson

• Publisher: Springer
• Year: 1994
• Tongue: English
• Weight: 717 KB
• Volume: 21
• Category: Article
• ISSN: 0340-6997
• DOI: 10.1007/bf00182356

✦ Synopsis

The rate of clearance from the lungs of inhaled technetium-99m labelled diethylene triamine penta-acetic acid (99mTc-DTPA) is often increased in interstitial lung disease as well as in smoking. In smokers a bi-exponential clearance course of 99mTc-DTPA when measured over 3 h has previously been shown. This study was performed to compare the kinetics of clearance of 99mTc-DTPA, measured for 3 h, in sarcoid patients and healthy smokers. Forty-one never-smoking patients with sarCoidosis and radiological signs of intrathoracic disease were studied. The results were compared with those of 16 healthy current smokers and of 14 healthy never-smokers reported previously. A mono-exponential clearance equation described the clearance in 22 of the sarcoid patients and all normal never-smokers, but with a shorter average tracer half-life in the patients (P<0.05). In 19 patients and all smokers a bi-exponential equation gave a significantly better curve fit. The rate of clearance of the slow component was higher in patients with sarcoidosis than in smokers (P<0.05). The fraction of the tracer cleared by the fast clearance component was smaller in patients with sarcoidosis than in smokers (P<0.01). Differences in kinetics of clearance of 99mTc-DTPA in sarcoidosis and smoking could thus be demonstrated, suggesting that the abnormal clearance is caused by diverging pathophysiological mechanisms.